AIR POLLUTION – MONITORING MODELLING AND HEALTH

Air Pollution and Cardiovascular Diseases 363
pollution to a larger extent than Western cohorts because they tend to spend more time
outside than indoors while Westerners have more access to air conditioning which tends to
mitigate pollution with the use of filters and recirculated ventilation. In the initial data
published in the PAPA study, Wuhan in mainland China exhibited highest concentrations
of PM10 and O 3 , while Shanghai has the highest concentrations of NO 2 and SO 2 . In
comparison with cities of comparable size in the U.S. (analyzing data from the National
Morbidity and Mortality and Air Pollution Study {NMMAPS}), the concentrations of PM10
and SO 2 were found to be much higher for cities included in the PAPA study. For example,
the concentrations of PM10 in PAPA had means of 52-142 μg/m3 versus 33 μg/m3 in
NMMAPS. In the case of NO 2 and O 3 , the results were similar in that U.S. had lower
concentrations than those in China 38 . When these results were correlated with mortality
figures for cardiovascular and respiratory diseases, predictable patterns emerged. Cause of
death ratios were the highest in Wuhan (4:1), followed by Shanghai (3:1) with lower figures
documented for Bangkok and Hong Kong 38 .
Banerjee et al have recently reported from India that exposure to poor air quality can alter
hematological and immunological parameters negatively. In their study, these investigators
reported results from 2218 individuals residing in the large urban metropolis of New Delhi
ranging in age from 21-65 years who were exposed to vehicular exhaust (the main polluter
of air quality in Asia in general and in India in particular). The authors found the prevalence
of hypertension 4 fold higher than matched controls (Bannerjee M et al, Int J Hyg Environ
Health 2011 Sep 16 Epub). Platelet P-selctins were significantly upregulated in this cohort
while CD4+ T-helper cells and CD19+ B cells were found to be depleted and CD56+ NK
cells were upregulated. These changes in the immune profile is positively correlated with
hypercoagulable states and higher cardiovascular risk 39 . These findings have been
effectively reproduced in other Indian studies as well. For example, Barman and colleagues
have recently published data from Lucknow (a city in Northern India) in which PM and
pollutant heavy metals were also linked to elevated risk of cardiovascular risk 40 . Even
earlier studies have shown strong correlation between air pollution levels and
cardiovascular risk. Nautiyal et al reported in a study completed in the Indian state of
Punjab (a pilot study) demonstrated positive correlations between angina pectoris and
PM10 pollution 41 .
Aside from cardiovascular mortality, other parameters of cardiovascular function have also
been correlated with greater air pollution. For example, in studies from central Europe, a
rise in blood pressure at times of greater air pollution has been reported. In the MONICA
study from Germany, a significant rise in blood pressure was noted in relation with
particulate air pollution even after adjustment for other cardiovascular risk factors 42 .
Significant elevations of diastolic blood pressure in 23 normotensive individuals following
two hours of exposure to PM2.5 were reported by Urch and colleagues 43 . In Brazil,,
monocyte levels also appear to significantly influence systolic, diastolic blood pressure
levels per quartile of monocyte concentration. In this setting, sulfur dioxide levels were also
noted to affect blood pressure, validating the importance of gaseous co-pollutants 44 .
Intriguingly, a large volume of data also suggests that the deleterious effects of particulate
air pollution can be aggravated by the presence of cofactors such as diabetes, obesity,
hypertension, chronic pulmonary disease, and previous cardiovascular disease, as well as an
additive effect of advancing age 45, 46 .